Projector lamp



' P. R. BASSETT PROJECTOR LAMP m H MN--." M 0 m W u w 1 M a gu Ill FiledNov. 25, 1922 leaf/0n for the electrodes of Patented May 29, 1928.

UNITED STATES PATENT OFFICE.

ASSIGNOR TO THE SPERRY GYRO- CORPORATION OF NEW YORK.

PROJECTOR LAMP.

Application filed November 25, 1922. Serial No. 608,288.

This invention relates to feeding means projector lamps, especially ofthe high intensity type. It is the principal object of this invention toprovide a lamp wherein the means for automaticall operating theelectrodes is highly reliable and accurate in its action, but isnevertheless simple in construction, of few parts, and light in weight.

s at present electrode (at least) as well as fed, and

constructed, the positive of these lamps is rotated separate means areused to rotate, feed and introduce current to the electrode. This notonly results in complications, but prevents the using of the last fourto six inches of each electrode by reason of the fact that theelectrodegripping means is necessarily located behind the brushes for introducingcurrent into the electrode. Bymy invention, I overcome this difficultyby a novel construction of brushes, whereby the brushes themselves notonly introduce current into the electrode, but also feed the same androtate it, if desired.

The feeding means is adapted to be used in connection with any controlsystem whether governed'by the voltage of the arc, the length of the areor the position of the carbon tips. The feeding means may be applied toeither the positive or.negative electrode, or to both.

A further object of the invention is the provision of means for feedingone ofthe electgedes at a constant rate, while the other electrode ismaintained in a given position.

In the accompanying drawings wherein I have shown what I now consider tobe the preferred form of my invention,

ig. 1 is a front View, vertically sectioned, of a projection lamp inwhich the, positive electrode feeding mechanism embodies my invention.

Fig. 2 is a detail of the electrode feeding mechanism embodying myinvention, the view being a plan of the mechanism as shown in Fig. I.

Fig. 3 is an end elevation of the positive electrode feeding mechanismof Fig. 1, showing the brush-returning member in inoperative position.

plurality of slots 20 outer ends thereof.

by means of a main Fig. 4 is a section taken on the line 4-4 of Fig. 2.

Fig. 5 is a diagrammatic view showing in plan one of the feeding-brushesin the rotary brush holder.

Fig. 6 is a diagrammatic showing a brush feeding representation of thepositive electrode mechanism about to be returned to starting positionby the rotating member.

ig. is a view similar to Fig. 6, but showing the brush returned tostarting position.

Fig. 8 is a detail of a holding bracket.

Fig. 9 is a view of the upper end of a modified form of brush-returningmember. Referring to the drawings, the lamp mechanism comprises a casing10 in which is positioned various operating mechanism to be describedhereinafter, and upon which are mounted supporting brackets 11 and 12,insulated from said casing, for holding the positive and negativeelectrodes, respectively. The bracket 11 is formed with a fixed hub 15bored centrally to permit an electrode 13 to slide therethrough.Rotatably mounted on the outside of the hub and bearing against ashoulder 16 thereof is a collar or brush-holder 17. The collar is heldagainst saidshoulder 16 and prevented from slipping off the hub by abifurcated holder 18 fixed to the bracket at 19 and operating against acircumferential shoulder 22 formed on the outside of the brush-holder.Said brush-holder is provided near the forward end thereof with apreferably symmetrically disposed and in each of which operates a brushor gripping member 21. In the device illustrated,' four slots areprovided in which operate four brushes. The slots are 9 formed to permitmovement of said brushes axially of the collar. The brushes are normallypressed into resilient engagement with the electrode by means of a.spring 25 (see Fig. 3) passing around the brushes and lodging in grooves26 (see Fig. 1) in the For the sake of clearness, the spring 25 has beenremoved in Fig. 1. Currentis supplied to the electrode lead 27 supplyingour- 109 rent to a brush 28 slidable on the outer surface of collar 17and from said collar to the brushes 21 by flexible conductor-strips 29.

For eeding the electrode (here shown as the positive electrode) eachbrush 21 is provided with a pin 30 fixedly secured thereto and extendingtherethrough parallel to the axis of the sleeve and the electrode. Thepins extend within the bore of the sleeve and when the brushes 21 are atthe outer (right, in the drawings) end of slots 20, one end of each ofsaid pins contacts with the inner (left) face of hub 15. Said face'is inthe form of a cam extending through a full 360 and then droppingabruptly to the starting point (see Figs. 6 and 7). It is obvioustherefore, that if the collar 17 is rotated, the ins will ride along theface of the cam an will be forced inwardly (to the left) together withthe brushes to which they are fixed. The brushes being in resilient,gripping engagement with the electrode, the latter will'be fed inwardly.For rotating the collar 17, the latter may be provided at its outer edgewith a bevel gear 38 which meshes with a pinion 39 at the upper end of arod having a worm 41 near its other end meshing with a worm gear 42 onthe shaft of a motor 43.

From the above description it will be apparent that once the pins 30have ridden successively to the steepest point (see Figs. 6 and '7) andbrushes 21 have reached the inner (left) end of the slots 20, they willremain in this position and no further'feeding of the electrode willtake place untilthe pins are moved outwardly into engagement with thelow point 37 of the cam 35. It is essential also that feeding shall takeplace only when the electrode has burned away sufliciently tonecessitate such feeding. Forthis purpose, means are provided forreturning the pins and their brushes to low portion 37 of the cam, inrotation and preferably one at a time, so that While the remainingbrushes (in this case, three) hold the electrode against outwardmovement, a less number of brushes (in this case one) may be movedoutwardly into contact with part 37 of the cam. Means are providedfurther, for rendering the' brush-returning means effective only whenfeeding of the electrode is required.

The feeding of the electrode 13 may be controlled by a third electrode45, as shown, or by any other controlling device such as a thermostat,designed to close'a circuit, when the carbon. has burned awaysufficiently,

through anelectro-magnet 46 with which cooperates one end of an armature47 When bracket 11 at the inner end thereof to shield the electromagnetattracts'said armature, the other end thereof engages a flange 51 on rod48 carrying a member '49 at its upper end to 'move said member into thepath of pins 30. Member 49 is provided withan inclined cam 36 of the camsurface 50 positioned so that a pin 30 strikes said surface just as said.pin reaches the highest point of the cam 35. A slight further movementof the pin causes ittodrop off cam 35, and still further movement alongthe -surface 50 causes said 'pin to be moved in counter-feedingdirection into engagement with the low portion 37 of said cam, and hencemoves the brushes 21 to the outer ends of slots 20. Although the returnmovement of the brushes is in a direction opposite to that of feedin theelectrode is not drawn outwardly to lengthen the are because the otherthree brushes are either stationary or moving the electrode inwardly infeeding direction, that is, as long as less than half the total numberof brushes are being returned,

(1 there will be more brushes holding the electrode against returnmovement and the electrode will not be fed backwards. It is thusapparent that as long as electromagnet 46 is energized, i. e., as longas there is necessity for feeding theelectrode 13 inwardly, member 49will be effective to return the brushes one after the other insuccession to the low point of cam 35, where by the continuous rotationofbrush-holder 17, the brushes will again move inwardly to continuefeeding said electrode. When the proper feeding position is reached, thecircuit through electromagnet 46 is broken, member 49 is moved toinoperativepositon, and as soon as all of the brushes 21 have been movedto the inward extremities of slots 20, no further feeding will takeplace. 'Should the member 49 be rendered effective at a time when it isdirectly underneath a pin 30, the upward movement said member isprevented by neath one arm of said armature limits the movement of thelatter in ineffective position, and to relieve the magnet of a heavyload, a spring 55 may be interposed between the end of the armaturesupporting meg-4s and a stop 56 If desired, the upper end of member 49may, in addition tothe cam-face 50 inclined laterally, be beveled as at60 (Fig. 9) to provide an incline longitudinally, so that if member 49in rising encounters a pin 30, it will move said pin outwardl instead ofbeing held beneath the pin until the latter passes beyond said member.

Anasbestos shield 62 may be fixed to the electrode feeding mechanismfrom the effects of the arc, openings being provided through which thepositive electrode 13 and the control, or third electrode 45, extend.

fixed to casing 10 to provide 1 the necessary degree of counterbalance.

armature during this period away until only the negative The negativeelectrode may constant rate directly from the motor 43. For thispurpose, shaft 40 maybe provided at its lower end with a worm 65 meshingwith a worm 66 on the end of a shaft 67 journaled in brackets 68 fixedto casing 10, said shaft 67 At the outer end of shaft 67 is fixed a gear69 meshing with a gear 70 at one end of a shaft 71 journaled in brackets72 formin part of bracket 12. A bevel gear 7 3 at the other'end of shaft71 meshes with a bevel gear 74 at one end of a screw-threaded shaft 75journaled in brackets 76 forming part of bracket 12. A carriage 78 ismounted on shaft 7 5 and on guide-rod 80 for movement parallel to saidaxis when said shaft 75 is rotated. The negative electrode is held atits rear or outer end in said carriage, its forward end being supportedby bracket 76. The constant rotation of motor 43 thus continuously feedsthe negative electrode, the rate of feed depending upon the speed of themotor and the various gear ratios in the driving connections between themotor and the carriage 78. The positive electrode is thus held at agiven point and is fed to this point whenever it has burned away apredetermined amount, while the negative electrode is fed inwardlycontinuously at a constant rate.

It will be understood that the feed mechanism described tive electrodemay be employed for feeding electrode, or both electrodes, if desired.Also, other types of driving means may be employed between the motor 43and the negative electrode, and in place of cam 35, any other suitableeccentric surface may be employed.

It will thus be apparent that the electrode is rotated, fed and suppliedwith current by employing a single set of brushes. The brushes arepositioned adjacent the arc, and, as no other mechanism comes intocontact with the electrode, the latter can burn a very short stub isleft, thus reducing the portion of the electrode which is wasted.

In accordance with the provisions of the patent statutes, I have. hereindescribed the principle of operation of my invention, together with theapparatus, which I now consider to represent the best embodimentthereof, but I desire to have it understood that the apparatus shown isonly illustrative and that the invention can be carried out by othermeans. Also, while it is designed to use the various features andelements in the combination and relations described, some of these maybe altered and others omitted, without interfering with the more generalresults outlined and the invention extends to such use. I

Having herein described my invention be fed at a what I extendingthrough the casing.

a p s in connection with the posiand desire to secure by Letters 1. In aprojector lamp, an electrode, gripping means in continuous engagementwith said electrode, a cam engageable by said gripping means, said camand said means being so movable relatively that said means is moved infeeding direction.

In a projector lamp, an electrode, gripmeans in continuous engagementwith said electrode, a cam engageable by said gripping means, said cambeing disposed in a plane substantially perpendicular to the axis ofsaid electrode, said cam and said means being so rotatable relativelythat said means and said electrode are moved in feeding direction.

3. In a projector lamp, an electrode, a cam, means continuously securedto said electrode and engaging said cam, said electrode being sorotatable relative to said cam that said means and said electrode aremoved in feeding direction.

4. In a projector lamp, an electrode, gripping means in continuousengagement with said electrode, a cam engageable by said gripping means,said cam being disposed in a plane substantially perpendicular to theaxis of said electrode, said electrode being so rotatable relative tosaid cam that said means and said electrode are moved in feedingdirection.

In a projector lamp, feeding member, said electrode and member beingrelatively rotatable, means continuously secured to said electrode andengaging said member to move said electrode in feed ing direction duringrelative rotation of said electrode and member.

6. In a projector lamp, an electrode, gripping means in continuousengagement with said electrode to rotate and feed the same, a feedingmember engageable by said gripping means, said member and said electrodebeing relatively rotatable, said feeding member being adapted to movesaid gripping means in feeding direction during relative movement ofsaid member and electrode.

In a projector lamp, anelectrode, a plurality of gripping membersengaging said electrode, means for moving said gripping members infeeding direction and means rendered efiective'by burning away of theelectrode to a predetermined degree for returning said members inrotation to the starting position.

8. In a projector plurality of gripping members resiliently engagingsaid electrode, a feeding member for moving said gripping members infeeding direction a predetermined distance, and means rendered effectiveby burning away of the electrode to a predetermined degree for returningless than one half of said mem-' bers at a time to the startingposition.

an electrode, a

lamp, an electrode, a

till

9. In a projector lamp, an electrode, a plurality of gripping membersengaging said elect-rode, means for reciprocating sai members in feedingdirection and in counterfeeding direction, said means comprising a camengageable by said gripping members for moving a plurality of saidmembers simultaneously in feeding direction, a cam to engage and returnsaid gripping members one at a time in the opposite direction, and meanswhereby said cam is rendered eifective by burning away of the electrodeto a predetermined degree. f

10. In a projector lamp, an electrode, a plurality of gripping membersengaging said electrode, means for reciprocating sai members in feedingdirection and in counter-feeding direction, said means comprising afeeding member for moving a plurality of said gripping memberssimultaneously in feeding direction, and a cam normally in loweredposition out of engagement with said gripping members and adapted to beraised to effective position to engage and return said gripping membersone at a time in the opposite direction, and means whereby said cam israised to effective position by burning away of theelectrode to apredetermined degree.

ll. In a projector lamp, an electrode, a plurality of gripping membersresiliently engaging said electrode, said electrode and members beingintegrally rotatable, means 'for reciprocating said members in feedingdirection and in counter-feeding direction, said means comprising a camengageable by said gripping members during rotation thereof to move saidmembers in feeding direction, and a cam normally in lowered positionout-of the path of said members and adapted to be raised to effectiveposition, into the path of said members to engage and return saidmembers opposite direction, and means whereby said cam is raised toeffective position by burning away of the electrode to a predetermineddegree. I v

12. In a projector lamp, a hub, a collar rotatably mounted on said hub,an electrode extending through said gripping members carried 'bv saidcollar and yieldingly gripping said electrode, means for rotating saidcollar, said hub having a cam engage-able by said gripping members andso positioned as .to move said members in feeding direction duringrotation of said collar.

3. In a projector lamp, a hub, a collar rotatably mounted on said hub,an electrode extending through said hub, a plurality of gripping memberscarried by said collar and yieldingly gripping said electrode, means forrotating said collar, said hub having a cam engageable by said grippingmembers and so positioned as to move said members in said cam,

one at a time in the hub, a plurailty of" feeding direction to thesteepest point of said cam, and means for returning said grippingmembers one at a time to the lowest point of said cam.

14. In a projector lamp, an electrode, a plurality of gripping membersresiliently engaging said electrode, means for rotating said electrode.by rotating saidme'm'bers, a cam engageable by said members and sopositioned as to move said members in feeding direction to the steepestpoint of said cam, and means for returning said gripping members inrotation to the lowest point of said cam.

15. In a projector lamp, plurality of gripping engaging said electrode,means for rotating said electrode by rotating said members, a camengageable by said members and so poan electrode, a

sitioned as to move said members in feeding direction to the steepestpointof said cam, a cam to engage and return said gripping members inrotation to the lowest point of and means whereby said cam is renderedeffective by burning away of the electrode to a predetermined degree.

16. In a projector lamp, plurality of gripping members resilientlyengaging said electrode, means for rotating said electrodeby rotatingsaid members, a cam engageable'by said members and so poan electrode, a

members resilientlysitioned as to-move said members in feeding directionto the steepest point of said cam, a cam normally in ineffectiveposition out of engagement with said gripping members and adapted to bemoved to effective position to engage and return said gripping membersin rotation to the lowest point of the cam,

and means whereby said cam is moved to effective position by burningaway of the electrode to a predetermined degree' 17. In a projectorlamp, a hub, a collar rotatably mounted on said hub, an, electrodeextending through said hub, a plurality of gripping members carried bysaid collar and resiliently gripping said electrode, means for rotatingsaid collar, said hubhaving a cam engageable by said gripping membersand so positioned asto move said members in feeding direction to thesteepest point of said cam, a cam to engage and returnsaid grippingmembers one at a time to the lowest point of the cam, and means wherebysaid cam is rendered effective by burning away of the electrode.

18. In a projector lamp, a hub, a collar rotatably mounted on said hub,an electrode extending through said gripping members carried by saidcollar and resiliently grippingsaid electrode, means for rotating saidcollar, said hub having a cam engageable by said gripping members and sopositioned as to move said members in feeding direction to the steepest.point of said cam, and a cam normally in ineffective hub, a plurality ofI movlng said comprising a plurality of position out of engagement withping members and adapted to be moved to effective posit-ion to engageand return said gripping members one at a time to the lowest point ofthe cam, and means whereby said cam is raised to effective position byburning away of the electrode to a predetermined degree.

19. In a projector lamp, an electrode, a plurality of gripping membersresiliently engaging said electrode, means for rotating said electrodeby rotating said members, a cam engageable by said members and sopositioned as to move said members in feeding direction to the steepestpoint of said cam, a second cam means whereby said second cam isrendered effective by burning away of the electrode to apredetermineddegree to engage and return said gripping members one at atime'to the lowest point of said first cam and rendered ineffective whensaid electrode reaches a predetermined position.

20. In a projector lamp, an electrode, a plurality of gripping membersresiliently engaging said electrode, a. feeding member for grippingmembers in feeding direction apredetermined distance, means renderedeffective by burning away of the electrode to a predetermined degree forreturning said members only one at a time to the starting position, andmeans for ing said last-named means ineffective when said electrodereaches a predetermined position.

21. In a projector lamp, meansfor feeding said electrode, said meanscomprising a brush-holder, a plurality of brushes in said holder saidgripmoving said brushes 1n said holder axially of said electrode infeeding, direction.

22. n a projector lamp, an electrode, and means for feeding saidelectrode, said means comprising a brush-holder, a. plurality of brushesin said holder and engaging said electrode, means for moving saidbrushes in said holder axially of said electrode in feedmg direction,and means for returning said brushes less than half at'a time to thestarting posit-ion.

23. In a projector lamp, an electrode, and means for feeding saidelectrode, said means current conductlng brushes in resilient engagementwith said electrode, and means for moving said brushes axially of saidelectrode in feeding direction.

24. In a engagement with said electrode, means for moving said brushesaxially of said electrode in feeding direction, and means renderedeffective by burning away of the electrode to a an electrode, and.

predetermined degree for returning said brushes one at a time tostarting position.

25. In a projector lamp, an electrode, and means for feeding saidelectrode, said means comprising a plurality of brushes in resilientengagement with said electrodes, means for moving said brushes axiallyof said electrode in feeding direct-ion, means rendered elfective byburning away of the electrode to a predetermined degree for returningsaid brushes one at a time to starting position and rendered ineffectivewhen said electrode is fed to a predetermined position.

26. In a projector lamp, an electrode, a hub, a brush-holder rotatablymounted on said hub, a plurality of brushes slidable in said holder andresiliently engaging said electrode, a cam on Said hub, a pin fixed toeach of said brushes and engaging said cam, and means for rotating saidholder to cause movement of said brushes in feeding direction.

27. In a projector lamp, an electrode, a hub, a brush-holder rotatablymounted on said hub, a plurality of brushes slidable in said holder andresiliently engaging said electrode, a. cam on said hub, a pin fixed toeach of said brushes and engaging said cam, said pins being positionedparallel to the axis of said electrode and substantially perpendicularto'said cam so that rotation of said holder causes movement of saidbrushes in feeding direction to the steepest, point of said cam.

28. In a projector lamp, an electrode, a hub, a brush-holder rotatablymounted on said hub, a plurality of brushes slidable in said holder andresiliently engaging said electrode, a cam on said hub, a pin fixed toeach of said brushes and engaging said cam,

said pins being positioned parallel to the said electrode andsubstantially per-i axis of pendicular to said cam so that rotation ofsaid holder causes movement of said brushes in feeding direction to thesteepest point of said cam, a cam member normally in ineffectiveposition out of the path of said pins but adapted to be moved toeffective position in said path to engage said pins and'return saidbrushes to the lowest point of said cam,

and means whereby said cam is moved to effcctive position when theelectrode burns away to a predetermined degree.

29. n a projector lamp, an electrode, a hub, a brush-holder rotatablymounted on said hub, a plurality of brushes slidable in said holder andresiliently engaging said electrode, a cam on said hub, a pin fixed toeach of said brushes and engaging said cam, said pins being positionedparallel to the axis of said electrode and substantially perpendicularto said cam so that rotation of said holder causes movement of saidbrushes in feeding direction to the steepest point of i said cam,

a cam member normally in ineffectix 'e posit-ion out of thepath of saidpins but adapted to be moved to effective position in said path toengage said pins and return said brushes to the lowestpoint of said cam,means for moving said second cam to eflective position when theelectrode burns away to a predetermined degree, and means for movingsaid second cam to inefiectlve p051 tion when said electrode is fed to apredetere 10 mined point V In testimony whereof I have aflixed my

